The invention described herein may be manufactured and used by and for the Government of the United States of America for Governmental purposes without the payment of any royalties thereon or therefor.
(1) Field of the Invention
The invention relates to antenna assemblies and is directed more particularly to an extension system for moving a navigational antenna, or the like, from a compact state within the hull of an underwater vehicle to an extended state wherein the antenna extends outwardly beyond the hull of the vehicle.
(2) Description of the Prior Art
It is known to provide an unmanned underwater vehicle (UUV) for carrying out a mission without risk of loss of human life. It often is beneficial to launch a UUV from a submerged submarine, more particularly from one of the submarine""s torpedo tubes, requiring that the UUV be of a round configuration widthwise and a compact size, not exceeding twenty-one inches in diameter. No radiant projections from the hull of the UUV can be accommodated.
While computerized guidance systems for such UUVs are utilized, given the shifting currents, tides, underwater streams, and the like, it is difficult for the computer to identify with pin-point accuracy the current position of the UUV and therefore difficult to initiate absolutely true course changes, and the like.
It is known that through an existing Global Positioning System (GPS), a vessel with a navigational antenna, referred to as a xe2x80x9cGPS Antennaxe2x80x9d, can quickly ascertain its precise position, and that with such an input, a computerized guidance system can quickly compute and set in motion any required course change in order to reach a selected destination.
There is, then, a need for an antenna extension system which is capable of extending a compact antenna housed within a torpedo-size vessel, outwardly from the vessel to obtain a GPS fix, and return the antenna to its compact condition wholly within the UUV.
An object of the invention is to provide an antenna extension system operative to extend a GPS antenna, or other antenna, from a compact condition wholly inside a UUV, or other underwater vehicle, to a position extending therefrom, in order to obtain a GPS fix, and to return the antenna to its compact condition within the UUV.
With the above and other objects in view, as will hereinafter appear, a feature of the present invention is the provision of an antenna extension system for extending an antenna from an underwater vehicle. The system comprises a housing disposed wholly within the vehicle, a plurality of telescopically connected tiers extendible from a base tier disposed within the housing, an innermost of the tiers being adapted to support the antenna. A coaxial cable extends from a base portion of the housing and is fixed at a distal end to the antenna. A plurality of telescopically connected fairings are extendible from the housing and disposed around the tiers and the cable. A cap is fixed to a distal end of a distalmost of the fairings for enclosing the antenna. Extension of the telescopically connected tiers from the base tier moves the antenna from wholly inside the housing to a position extending outwardly from the vehicle, and extends the cable and fairings with the tiers.
The above and other features of the invention, including various novel details of construction and combinations of parts, will now be more particularly described with reference to the accompanying drawings and pointed out in the claims. It will be understood that the particular device embodying the invention is shown by way of illustration only and not as a limitation of the invention. The principles and features of this invention may be employed in various and numerous embodiments without departing from the scope of the invention.